Automatic power regulating circuit applied to optical communication

The invention provides an automatic power regulating circuit applied to optical communication. The automatic power regulating circuit comprises a light emitting circuit, a photoelectric conversion circuit and a power regulation feedback circuit; the photoelectric conversion circuit receives a light signal emitted by the light emitting circuit, an output end of the photoelectric conversion circuitis connected with the power regulation feedback circuit, and the output end of the power regulation feedback circuit is connected with a control end of the light emitting circuit. According to the automatic power regulating circuit, the voltage obtained by photoelectric conversion is compared with the threshold of a window comparator, the comparator of an analog part outputs a corresponding signalto a digital logic circuit and then outputs 12-bit data to a bias current circuit so as to regulate the bias current of a light emitting diode to change the light transmitting power of the light emitting diode, and finally the voltage signal output by the light emitting diode is kept near a window common mode level so as to maintain the light transmitting power of the light emitting diode withina set range and to maintain the communication quality.